Electronic systems can include analog-to-digital (A/D) converters (ADCs). Converting analog signals to digital quantities allow processors of electronic systems to perform signal processing functions for the systems. The sigma delta ADC is one type of ADC and is used in converting signals in the audio band and in precision industrial measurement applications. Integrated circuit continuous time sigma delta ADCs can have poor performance on direct current (DC) signals. The present inventors have recognized a need for improved performance of ADCs.